Augmented EM Propulsion System

ABSTRACT

An electromagnetic missile launcher is disclosed that avoids some of the costs and disadvantages of missile launchers in the prior art. In particular, an embodiment of the present invention uses a pilot accelerator that comprises an electromagnetic booster coil to improve the efficiency of an electromagnetic catapult that throws a missile clear of the launch platform—with sufficient velocity to attain aerodynamic flight—before the missile&#39;s engine is ignited.

This invention was made with Government support under CooperativeResearch and Development Agreement No. SC99/01573 awarded by theDepartment of Energy. The Government has certain rights in theinvention.

FIELD OF THE INVENTION

The present invention relates to missilery in general, and, moreparticularly, to missile launchers.

BACKGROUND OF THE INVENTION

A missile is propelled by fuel and a chemical-propulsion engine. Achemical-propulsion engine propels a missile by the reaction thatresults from the rearward discharge of gases that are liberated when thefuel is burned. For the purposes of this specification, a “missile” isdefined as a projectile whose trajectory is not necessarily ballisticand can be altered during flight (as by a target-seeking radar deviceand control elements).

When a missile is launched, the discharge of the hot gases causesseveral problems. First, the hot gases heat the launch platform, whichrenders the launch platform more visible to enemy infrared sensors and,therefore, more vulnerable to attack. Second, the hot gases can obscurethe ability of personnel in the area of the launch platform to see,which might impair their ability to perform routine tasks, such asdetecting enemy threats. Third, the brightness of the flame exiting theengine can—especially at night—temporarily blind the launch-platformpersonnel. Fourth, the missile's fuel often includes an aluminizedcompound that is dispersed in the atmosphere surrounding the launchplatform, which can impair the operation of radar systems near thelaunch platform. And fifth, as modern missiles become larger, theirgases become hotter and more voluminous, and, therefore, cannot beadequately vented within the launching platform using currenttechnology.

Electromagnetic missile launchers (EMMLs) have been developed tomitigate some of the damaging effects of a chemically-based missilelaunch, In the prior art, such as U.S. patent application Ser. No.10/899,234, filed on 26 Jul. 2004, which is incorporated by referenceherein, an EMML typically utilizes electromagnetic coils around a guiderail to propel an armature on which is mounted to a missile.Inefficiencies inherent to this propulsion method, however, dictate thatthe electromagnetic coils be larger, more numerous, and carry moreelectric current than desirable. The additional infrastructure adds tolauncher cost and complexity. In addition, the power system used tocontrol the flow of electric current in the electromagnetic coils mustbe made larger so as to manage the increased electric current as well astransients that develop through the course of a missile launch. Thereexists a need, therefore, for a missile launch system that avoids ormitigates some or all of these problems.

SUMMARY OF THE INVENTION

The present invention provides a technique for launching a missile thatavoids some of the costs and disadvantages for doing so in the priorart. In particular, the illustrative embodiment of the present inventionuses a pilot accelerator to accelerate an armature for throwing amissile from its rest position into motion toward a series of rail coilsthat sustain the acceleration of the armature.

In the illustrative embodiment, an electromagnetic coil arrangementincludes a propulsion coil—the pilot accelerator—that is located behindthe missile armature so as to direct its propulsive force on thearmature along the launch axis. This provides a more efficient means ofinitiating the motion of the armature than is known in the prior art.The coupling efficiency of the electromagnetic force generated by therail coils is improved by the use of the pilot accelerator, whichresults in an improvement in efficiency of the overall launcher system.This mitigates some of the problems associated with launching missilesin the prior art.

An embodiment of the present invention comprises: an outer coil that hasa longitudinal axis; an armature that comprises an armature coil that isconcentric with the outer coil, wherein the outer diameter of thearmature coil is smaller than the inner diameter of the outer coil; anda pilot accelerator for imparting a first force to the armature, whereinthe first force is directed along the longitudinal axis of the outercoil; wherein a second force on the armature is based on the mutualinductance of the outer coil and the armature coil; and wherein thefirst force accelerates the armature from a rest position toward theouter coil so as to increase the mutual inductance of the outer coil andthe armature coil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic diagram of an electromagnetic launch systemin accordance with an embodiment of the present invention.

FIG. 2 depicts a cross-sectional view of an electromagnetic missilelauncher in accordance with the prior art.

FIG. 3 depicts a cross-sectional view of a side-load electromagneticcoil in accordance with the prior art.

FIG. 4 depicts a cross-sectional view of a normal-load electromagneticcoil in accordance with an embodiment of the present invention.

FIG. 5 depicts a cross-sectional view of an electromagnetic launcheraccording to an embodiment of the present invention.

FIG. 6 depicts a flowchart of the salient tasks associated with arepresentative launch sequence, in accordance with the illustrativeembodiment of the present invention.

DETAILED DESCRIPTION

The following terms are defined for use in this Specification, includingthe appended claims:

-   -   Physically-connected means in direct, physical contact and        affixed (e.g., a mirror that is mounted on a linear-motor).    -   Physically-coupled means in direct, physical contact, although        not necessarily physically-connected (e.g., a coffee cup resting        on a desktop).    -   Pilot accelerator means a device or structure for imparting        acceleration to an armature. Examples of pilot accelerators        include, without limitation, a compressed gas system, an        explosive charge, or a mechanical-energy storage device, such as        a spring. Examples of pilot accelerators do not include a        side-coupled electromagnetic coil (i.e., a rail coil).

FIG. 1 depicts a schematic diagram of an electromagnetic launch systemin accordance with an embodiment of the present invention.Electromagnetic launch system 100 comprises electromagnetic launcher 102(hereinafter, launcher 102), launch controller 104, weapons controlsystem 106, power system 108, control cable 110, signal line 112, andcurrent cable 114.

Launcher 102 is a system that has the capability to house and expel oneor more missiles upon command. The system expels each missile from anassociated launch cell using an electromagnetic catapult and without theaid of the missile's chemical-propulsion engine. This is advantageousbecause it enables the missile to clear the launch platform before itignites its engine, thereby avoiding some of the problems discussed inthe Background section. Although in the illustrative embodimentelectromagnetic launch system 100 comprises an electromagnetic launcherhaving a single launch cell, it will be clear to those skilled in theart, after reading this specification, how to make and use alternativeembodiments of the present invention wherein launcher 102 comprises morethan one launch cell.

Launch controller 104 provides the targeting and flight information to amissile prior to launch and the directive to launch to power system 108.

Weapons control system 106 provides targeting and flight information andfiring authority to launch controller 104 prior to and during a launchsequence. It will be clear to those skilled in the art, after readingthis disclosure, how to make and use weapons control system 106.

Power system 108 comprises circuitry that conditions and manages thestorage and delivery of power to, and the recover of power from,launcher 102 in response to signals from launch controller 104. Powersystem 108 controls power generation, scavenging, storage, and deliveryprior to, during, and after each launch. Power system 108 is describedin detail in U.S. patent application Ser. No. 10/899,234, filed on 26Jul. 2004, which is incorporated by reference herein.

Control cable 110 carries the targeting information from launchcontroller 104 to the missile and sled position information fromsled-position sensor 322 (shown in FIG. 3) to launch controller 104.

Signal line 112 connects launch controller 104 to power system 108 andcarries the commands that direct power system 108 to initiate andcontrol the launch of a missile.

Current cable 114 carries power from power system 108 to launcher 102.In some embodiments of the present invention that comprise multiplelaunch cells, current cable 114 is capable of carrying power to eachlaunch cell independently from the other launch cells.

FIG. 2 depicts a cross-sectional view of an electromagnetic missilelauncher in accordance with the prior art. Electromagnetic launcher 200(hereinafter, launcher 200) comprises missile 202, sled 204, guide rail206, missile canister 208, sled coil 210, and rail coils 212-1 and212-2. As described in U.S. patent application Ser. No. 10/899,234,during a missile launch, launcher 200 throws missile 202 with sufficientvelocity to obtain aerodynamic flight such that missile 202 travels somedistance away from launcher 200 before the missile's chemical-propulsionengine ignites.

Missile canister 208 encloses missile 202, sled 204, guide rail 206, andrail coils 212-1 and 212-2 in a substantially air-tight environment.

Missile 202 comprises a chemical-propulsion engine and an explosivewarhead.

Sled 204 comprises a rigid platform for holding a missile, sled coil210, and bearings 214 for guiding sled 204 along guide rail 206. Sledcoil 210 is an electrical conductor that has a helical shape and isimmovable with respect to sled 204. Prior to launch, missile 202 isattached to sled 204 by actuatable missile restraint bolts (not shownfor clarity) and sled 204 is attached to missile canister 208 by sledrestraint bolt 214.

Rail coils 212-1 and rail coil 212-2 each comprise a helix of electricalconductor, wherein each helix has an inner diameter larger than theouter diameter of the sled coil, and wherein the electrical conductor iscapable of carrying sufficiently high voltage/amperage to enablesufficient launch power.

During a missile launch, electric current is first directed to flowthrough sled coil 210 and rail coil 212-1 by a power management system.The current flow induces a force on sled 204 that is partially directedalong launch axis 216. The magnitude of the electromagnetic force onsled 204 is a function of the currents in sled coil 210 and rail coil212-1 and the gradient of their mutual inductance. The electromagneticforce increases until it is sufficient to break sled restraint bolt 216and propel sled 204 (and attached missile 202) along launch axis 218toward the muzzle end of launcher 200. The power management systemsequences and controls current flow in sled coil 210, rail coil 212-1and rail coil 212-2 during missile launch to continue the accelerationof sled 204 along launch axis 218 until sufficient velocity is obtainedto throw missile 202. At a predetermined velocity, the missile restraintbolts are actuated (i.e., broken) and the power management systemchanges the current flow in sled coil 204 and rail coils 212-1 and 212-2so as to decelerate sled 204 such that the missile disengages from thesled. After it disengages from sled 204, missile 202 exits the muzzleend of launcher 200 and achieves aerodynamic flight. Prior to the lossof aerodynamic flight, and after missile 202 achieves sufficientseparation from launcher 200, the chemical-propulsion engine of themissile is ignited and missile 202 continues toward its target.

At the beginning of the launch sequence, the electromagnetic force onsled 204 is generated by the flow of electric current in the sled coiland rail coils. The magnitude of that force is a function of the mutualinductance of these coils. Rail coils 212-1 and 212-2 are “side-load”electromagnetic propulsion elements, as will be described below and withrespect to FIG. 3. The electromagnetic force generated by side-coilelements is not efficiently coupled into motion of sled 204 along launchaxis 218. The coupling of the mutual inductance of sled coil 210 andrail coils 212-1 and 212-2 is particularly inefficient when sled 204 isin its rest position at the breech end of launcher 200. Unfortunately,the acceleration of missile 202 from rest (and breaking sled restraintbolts 216) is the least efficient step in the launch sequence forconverting electrical energy to kinetic energy—much less efficient thanthe energy conversion required for accelerating an already movingmissile 202. Because of the need to perform this inefficient conversion(necessary only at the beginning of a launch), more rail coils or railcoils 212-1 and 212-2 need to be made larger and more complex than wouldbe required to accelerate a missile already in motion. The addedinfrastructure, including a more powerful power management system,increases the size, weight, cost, and complexity of launcher 200.

The mutual inductance between a coil and an armature is a function ofthe number of coil windings and the magnitude of the electric currentflowing in the coil. The force exerted between the coil and armaturearises from a gradient in the mutual inductance between them. Thedirectionality of that force is a function of the relative positions ofthe coil and armature (i.e., the way the electromagnetic field couplesto the armature). The rail coils described above are examples of“side-load” electromagnetic coils. Much of the force generated between aside-load coil and an armature is in the direction between the coil andthe armature. In the case of an electromagnetic missile launcher,however, it is most desirable to direct the force applied to an armaturealong the launch axis of the missile launcher.

In a maximally-efficient electromagnetic missile launch system, all ofthe generated electromagnetic force is directed along the launch axis.As is described below and with respect to FIG. 4, a “normal-load”electromagnetic coil substantially increases the portion of generatedelectromagnetic force applied to an armature along the launch axis. Inthe present invention, a normal-load electromagnetic coil is used as apilot accelerator to accelerate an armature from its rest positiontoward a series of concentric side-load electromagnetic coils (i.e.,rail coils). The rail coils sustain the acceleration of the armature inknown fashion.

FIG. 3 depicts a cross-sectional view of a side-load electromagneticcoil in accordance with the prior art. Side-load electromagnetic coil300 comprises rail coil 304 and its rail coil windings 306. Magneticflux lines 308, generated in response to the flow of electric current inrail coil windings 306, are influenced by the presence of armature 302and have the characteristic shape as shown. A significant amount of theelectromagnetic force applied to armature 302 is directed between sledcoil 310 and rail coil windings 306, rather than along the launchdirection. As a result, side-load rail coil 300 propels armature 302along the launch direction with less than maximum efficiency.

FIG. 4 depicts a cross-sectional view of a “normal-load” electromagneticcoil in accordance with an embodiment of the present invention.Normal-load electromagnetic coil 400 comprises booster coil windings402. Magnetic flux lines 404 are generated in response to the flow ofelectric current in booster coil windings 402, and are influenced by thepresence of armature 302. In the case of normal-load electromagneticcoil 400, the launch direction is aligned with the direction of themajority of the generated electromagnetic force. As a result,normal-load electromagnetic coil 400 propels armature 406 along thelaunch direction with higher efficiency than side-load electromagneticcoil 300.

Since it is more efficient, the arrangement of propulsion coils depictedin FIG. 4 enables a reduction in at least some of size, weight, numberof turns, magnitude of current flow, and complexity of power system forelectromagnetic launch system 100, as compared to those known in theprior art.

FIG. 5 depicts a cross-sectional view of an electromagnetic launcheraccording to an embodiment of the present invention. Launcher 102comprises missile 202, armature 502, guide rail 504, missile canister506, pilot accelerator 508, rail coils 510-1 through 510-3,sled-position sensor 512 and current umbilical 516.

Missile canister 506 provides a substantially air-tight environment formissile 202, armature 502, guide rail 504, pilot accelerator 508, railcoils 510-1 through 510-3, and current umbilical 516, in well-knownfashion. In some alternative embodiments of the present invention, someof pilot accelerator 508 and rail coils 510-1, 510-2, and 510-3 arelocated outside missile canister 506.

Missile 202 comprises an explosive warhead, a chemical-propellantengine, and accelerometer 520 for providing acceleration information asis well-known in the art. It will be clear to those skilled in the art,after reading this disclosure, how to make and use missile 202.

Armature 502 comprises sled 520, sled coil 522, and reflector 524. Sled520 comprises a rigid platform of suitable size for supporting missile202. Sled coil 522 comprises a helical coil of electrical conductor,capable of carrying sufficiently high voltage/amperage to enablesufficient launch power, and sled coil 522 is substantially immovablewith respect to sled 520. The mutual inductance of sled coil 522 andbooster coil 514 generates an electromagnetic force along axis 518 whenbooster coil 514 is energized with electric current. In similar fashion,the mutual inductance of sled coil 522 and each of rail coils 510-1through 510-3 generates an electromagnetic force along axis 518 when oneor more of rail coils 510-1 through 510-3 is energized with electriccurrent. Reflector 524 is a mirror for reflecting an optical beam backto sled-position sensor 512 in known fashion. In some embodiments of thepresent invention, sled coil 514 is carries electric current supplied bypower system 108. In these embodiments, the direction of electromagneticforce generated by sled coil 522 along axis 518 depends on the directionof current flow in sled coil 522.

Prior to a launch, armature 502 is rigidly attached to missile canister506 by a sled restraint bolt, and missile 202 is attached to armature502 by missile restraint bolts. Bearings for guiding armature 502 alongguide rail 504, the missile restraint bolts, and the sled restraint boltare not shown for clarity. It will be clear to those skilled in the arthow to make and use sled bearings, missile restraint bolts, and sledrestraint bolts. It will be clear to those skilled in the art, afterreading this disclosure, how to make and use armature 502.

Guide rail 504 comprises four vertical members that provide structuralsupport for missile canister 506, pilot accelerator 508, and rail coils510-1 through 510-3 which are affixed to guide rail 504 in asubstantially-immovable manner. Guide rail 504 also provides straight,smooth tracks against which the sled bearings ride during a launch.Although the illustrative embodiment comprises four (4) verticalstructural members, it will be clear to those in skilled in the art,after reading this disclosure, how to make and use embodiments of thepresent invention that comprise any number of vertical structuralmembers.

Pilot accelerator 508 is located behind the rest position of armature502 on axis 518 and comprises booster coil 514. Booster coil 514 is ahelix of electrical conductor capable of carrying sufficiently highvoltage/amperage to enable sufficient electromagnetic energy to: (1)initiate motion of armature 502 from a rest position; and (2) propelarmature 502 into a suitable position for continued acceleration byelectromagnetic force generated by rail coil 510-1. Booster coil 514generates electromagnetic force along axis 518 when energized withelectric current. The direction of electromagnetic force generated alongaxis 518 by booster coil 514 depends on the direction of current flow inthe coil. It will be clear to those skilled in the art, after readingthis disclosure, how to make and use booster coil 514.

Current umbilical 516 comprises electrical conductors of sufficientlength to span the length of travel of armature 502 during a launch.Current umbilical 516 is electrically-connected to current cable 114 andprovides electrical connection of armature 502 to power system 108throughout the entire launch. Prior to the launch, targeting informationis passed from launch controller 104 to missile 202 via acanister-to-sled umbilical and sled-to-missile umbilical in similarfashion to current cable 516. For the sake of clarity, these umbilicallines are not shown in FIG. 5. It will be clear to those skilled in theart how to make and use current umbilical 516, and canister-to-sled andsled-to-canister umbilicals.

Although the embodiment depicted in FIG. 5 employs an electromagneticbooster coil to provide pilot acceleration (i.e., acceleration ofarmature 502 from rest toward rail coil 510-1), in some alternativeembodiments of the present invention, a non-electromagnetic means ofaccelerating the armature from rest is provided. Suitable means forproviding pilot acceleration include, without limitation, mechanicalsprings, compressed gas or fluid, or explosive force. In somealternative embodiments of the present invention, wherein pilotacceleration is provided in a non-electrical manner, current umbilical516 is unnecessary.

Rail coils 510-i, where i=1 to 3, each comprise a helix of electricalconductor, wherein each helix has an inner diameter larger than theouter diameter of sled coil 522, and wherein the electrical conductor iscapable of carrying sufficiently high voltage/amperage to enablesufficient launch power. Each rail coil 510-i generates electromagneticforce along axis 518 when energized with electric current. The directionof electromagnetic force that is generated along axis 518 by each ofrail coils 510-i depends on the direction of current flow in that coil.It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use rail coils 510-i.

Sled-position sensor 512 is an optical range-finding device on thebottom of missile canister 506. Sled-position sensor 512 transmits anoptical beam at reflector 524, which is located on the bottom ofarmature 502, and determines the position of armature 502 based on thetime-of-travel of the reflected optical beam. The position of armature502 is used by launch controller 104 to sequence current flow in boostercoil 514 and rail coils 510-1, 510-2, and 510-3. In some embodiments,the position of armature 502 is used by launch controller 104 to controlcurrent flow in sled coil 522. It will be clear to those skilled in theart, after reading this disclosure, how to make and use sled-positionsensor 512 and reflector 524.

Referring now to FIGS. 5 and 6, a representative missile launch sequenceis described. At task 601, weapons control system 106 passes launchauthority and target information to launch controller 104.

At task 602, launch controller 104 passes target information to missile202.

At task 603, power system 108 energizes booster coil 514 with currentsupplied on current cable 114. Power system 108 controls the flow ofelectric current in booster coil 514, which is substantially immovablewith respect to missile canister 506. The current flow is controlledsuch that a first electromagnetic force is generated along axis 518 bybooster coil 514. The direction of the generated force is made so as tocause a repulsive force between armature 502 and booster coil 514 thatis directed along axis 518. When the magnitude of the repulsive forceexceeds a pre-determined threshold, the sled restraint bolt releases,and armature 502 is allowed to travel along axis 518 toward the muzzleend of launcher 102 and toward the interior volume of rail coil 510-1.In some alternative embodiments, power system 108 also controls the flowof electric current in sled coil 522. In some alternative embodiments,the current flow in sled coil 522 is controlled such that a secondelectromagnetic force is generated along axis 518 so as to increase theforce applied to armature 502. Due to its proximity and orientation withrespect to armature 502, the electromagnetic force generated by boostercoil 514 is more efficiently coupled to the armature 502 than theelectromagnetic force generated by rail coils in prior artelectromagnetic missile launchers.

At task 604, as armature 502 travels along axis 518, power system 108sequences the flow of current in booster coil 514 and rail coil 510-1 inorder to substantially maximize the efficiency of the propulsion ofarmature 502. As armature 502 continues its travel along axis 518, powersystem 108 sequences the flow of current in rail coils 510-1, 510-2, and510-3 to substantially maximize propulsion of armature 502 toward themuzzle end of launcher 102. The illustrative embodiment comprises fourpropulsion coils, booster coil 514, and rail coils 510-1, 510-2, and510-3. It will be clear to those skilled in the art, however, afterreading this specification, how to make and use alternative embodimentsof the present invention that comprise any number of coils that are:

-   -   i. continuous; or    -   ii. separate and on any suitable spacing; or    -   iii. inter-leaved along the length of guide rail 504; or    -   iv. any combination of i, ii, and iii.

At task 605, sled-position sensor 512 transmits a signal to launchcontroller 104 to indicate that armature 502 is nearing the end of itstravel along axis 518. In response, launch controller 104 changes theflow of electric current in coils 510-1 through 510-3 to begin todecelerate armature 502.

At task 606, accelerometer 520 senses the deceleration of armature 502and provides a signal that is used to (i) actuate the missile restraintbolts, and (ii) initiate ignition of the missile's chemical-propellantengine.

At task 607, armature 502 throws missile 202 with sufficient velocitythat missile 202 obtains aerodynamic flight away from launcher 102.

At task 608, the chemical-propellant engine is ignited once missile 202has achieved sufficient clearance from launcher 102 but before missile202 has lost aerodynamic stability.

It will be clear to those skilled in the art, after reading thisdisclosure, how to make and use accelerometer 520. Furthermore, it willbe clear to those skilled in the art, after reading this specification,how to make and use alternative embodiments of the present inventionthat use other means of initiating ignition of the chemical-propellantengine such as a signal from an altimeter, a timing circuit, a fuse, orsignal transmitted to missile 202 from weapons control system 106.

It is to be understood that the above-described embodiments are merelyillustrative of the present invention and that many variations of theabove-described embodiments can be devised by those skilled in the artwithout departing from the scope of the invention. For example, in thisSpecification, numerous specific details are provided in order toprovide a thorough description and understanding of the illustrativeembodiments of the present invention. Those skilled in the art willrecognize, however, that the invention can be practiced without one ormore of those details, or with other methods, materials, components,etc.

Furthermore, in some instances, well-known structures, materials, oroperations are not shown or described in detail to avoid obscuringaspects of the illustrative embodiments. It is understood that thevarious embodiments shown in the Figures are illustrative, and are notnecessarily drawn to scale. Reference throughout the specification to“one embodiment” or “an embodiment” or “some embodiments” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment(s) is included in at least one embodimentof the present invention, but not necessarily all embodiments.Consequently, the appearances of the phrase “in one embodiment,” “in anembodiment,” or “in some embodiments” in various places throughout theSpecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, materials, orcharacteristics can be combined in any suitable manner in one or moreembodiments. It is therefore intended that such variations be includedwithin the scope of the following claims and their equivalents.

1. An apparatus comprising: an outer coil having a longitudinal axis; anarmature comprising an armature coil that is concentric with said outercoil, wherein the outer diameter of said armature coil is smaller thanthe inner diameter of said outer coil; and a pilot accelerator fordirecting a first force on said armature along said longitudinal axis;wherein a second force on said armature is based on a mutual inductanceof said outer coil and said armature coil; and wherein said first forceaccelerates said armature from a rest position toward said outer coil soas to increase said mutual inductance.
 2. The apparatus of claim 1wherein said pilot accelerator comprises a booster coil that isconcentric with said armature coil, and wherein the outer diameter ofsaid booster coil is less than the inner diameter of said outer coil,and further wherein said booster coil is located behind said restposition.
 3. The apparatus of claim 2 further comprising a power systemfor controlling the flow of electric current through said outer coil,said booster coil, and said armature coil.
 4. The apparatus of claim 1wherein said pilot accelerator comprises a mechanical-energy storagedevice.
 5. The apparatus of claim 1 wherein said pilot acceleratorcomprises a compressed gas system.
 6. The apparatus of claim 1 whereinsaid pilot accelerator comprises an explosive device.
 7. The apparatusof claim 1 further comprising a missile, wherein said missile and saidarmature are physically-coupled.
 8. An apparatus comprising: an armaturefor throwing a missile, wherein said armature comprises a firstelectromagnet; a guide for propelling said armature, wherein said guidecomprises a second electromagnet; and a pilot accelerator; wherein afirst force on said armature is based on the flow of electric current insaid second electromagnet; and wherein said pilot accelerator exerts asecond force on said armature, and wherein said second force acceleratessaid armature from rest toward said first electromagnet so as toincrease the application of said first force on said armature.
 9. Theapparatus of claim 8 wherein said pilot accelerator comprises a thirdelectromagnet and wherein said third electromagnet has an outer diameterthat is less than the inner diameter of said second electromagnet. 10.The apparatus of claim 9 wherein said third electromagnet has an outerdiameter that is substantially equal to the outer diameter of said firstelectromagnet.
 11. The apparatus of claim 9 wherein said second force isbased on the flow of electric current in at least one of said firstelectromagnet and said third electromagnet.
 12. The apparatus of claim 8wherein said pilot accelerator comprises a compressed gas system. 13.The apparatus of claim 8 wherein said pilot accelerator comprises anexplosive device.
 14. An apparatus comprising: a missile; an outer coilfor applying a first force to an armature for throwing said missile,wherein said outer coil defines a cavity having a cavity diameter, andwherein said first force is based on the flow of electric current insaid outer coil; said armature, wherein said armature comprises aplatform and an armature coil that is substantially immovable withrespect to said platform, and wherein said armature has a rest positionthat is at least partially outside said cavity; and a pilot acceleratorfor applying a second force on said armature to accelerate said armaturefrom rest toward said outer coil, wherein said pilot accelerator has anouter diameter that is less than said cavity diameter, and wherein saidpilot accelerator is fixedly located behind said rest position.
 15. Theapparatus of claim 14 wherein said first force is based on the mutualinductance of said outer coil and said armature coil.
 16. The apparatusof claim 14 wherein said pilot accelerator comprises a booster coil, andwherein said second force is based on the flow of electric current insaid booster coil.
 17. The apparatus of claim 16 wherein said armaturecomprises an armature coil, and wherein said second force is based onthe mutual inductance of said booster coil and said armature coil. 18.The apparatus of claim 14 wherein said armature comprises an armaturecoil, and wherein said second force is based on the flow of electriccurrent in said armature coil.
 19. The apparatus of claim 14 whereinsaid pilot accelerator comprises a compressed gas system.
 20. Theapparatus of claim 14 wherein said pilot accelerator comprises anexplosive device.